SHA-256 algorithm
This algorithm is used by the Key Test and Key Test2 callable services to generate and verify the verification pattern.
VP = Trunc64( SHA256( KA || K ))
Where:
- VP is the 64-bit verification pattern.
- TruncN(x) is truncation of the string x to the left most N bits.
- SHA256(x) is the SHA-256 hash of the string x.
- KA is the one-byte CCA variable-length key token constant for the algorithm of key (AES X'01').
- K is the clear key value left-justified and padded on the right with binary zeros to byte boundary.
- || is string concatenation.